My background: I've had an Auzentech X-Fi Prelude 7.1 for the longest time. Being a legacy PCI card, I was stuck using my GPU in the 2nd PCI-E slot which lead to degraded performance (albeith very little), but more importantly higher temps.
-Works as intended; -Has DTS encoding which I wanted; -Uses PCI-express; -External module for Headphones
-Expensive; -External module loss of quality (apparently